Association between Sense of Coherence, Disease-Specific Symptoms, and Health-Related Quality of Life among Japanese Patients with Ulcerative Colitis: A Cross-Sectional Study

Introduction: We examined the associations among disease-related symptoms, health-related quality of life (HRQOL), and sense of coherence (SOC) in Japanese patients with ulcerative colitis (UC). Methods: This cross-sectional survey involved patients and physicians at 23 hospitals specializing in UC treatment in Japan (December 2019–December 2020). Multiple linear regression analysis was performed using scores on the Mental Health and General Health subscales of the Medical Outcomes Study 36-Item Short-Form Health Survey as outcomes and SOC as the main independent variable. Scores on the Inflammatory Bowel Disease Questionnaire (IBDQ) and Fecal Incontinence Quality of Life Scale (FIQL) were used to measure the effect of disease-related symptoms. The moderating effect of symptoms on the association between HRQOL and SOC was also tested. Results: SOC was positively and independently associated with HRQOL (Mental Health: β = 0.43, 95% confidence interval [CI] = 0.24–0.61, p < 0.001; General Health: β = 0.41, 95% CI = 0.23–0.59, p < 0.001). The association of SOC with Mental Health scores did not differ by symptoms, whereas its association with General Health was attenuated by symptoms (interaction term of IBDQ by SOC: β = −0.0082, 95% CI = −0.017 to 0.00064, p = 0.07; that of FIQL by SOC: β = −0.0052, 95% CI = −0.011 to 0.0010, p = 0.10). Conclusions: SOC affected mental health independently, and its protective association with general health perception was affected by symptoms. Further research is required to determine the most effective use of SOC in interventions to improve HRQOL in patients with UC.